Book Image

Solidity Programming Essentials - Second Edition

By : Ritesh Modi
Book Image

Solidity Programming Essentials - Second Edition

By: Ritesh Modi

Overview of this book

Solidity is a high-level language for writing smart contracts, and the syntax has large similarities with JavaScript, thereby making it easier for developers to learn, design, compile, and deploy smart contracts on large blockchain ecosystems including Ethereum and Polygon among others. This book guides you in understanding Solidity programming from scratch. The book starts with step-by-step instructions for the installation of multiple tools and private blockchain, along with foundational concepts such as variables, data types, and programming constructs. You’ll then explore contracts based on an object-oriented paradigm, including the usage of constructors, interfaces, libraries, and abstract contracts. The following chapters help you get to grips with testing and debugging smart contracts. As you advance, you’ll learn about advanced concepts like assembly programming, advanced interfaces, usage of recovery, and error handling using try-catch blocks. You’ll also explore multiple design patterns for smart contracts alongside developing secure smart contracts, as well as gain a solid understanding of writing upgradable smart concepts and data modeling. Finally, you’ll discover how to create your own ERC20 and NFT tokens from scratch. By the end of this book, you will be able to write, deploy, and test smart contracts in Ethereum.
Table of Contents (21 chapters)
1
Part 1: The Fundamentals of Solidity and Ethereum
7
Part 2: Writing Robust Smart Contracts
13
Part 3: Advanced Smart Contracts

Reentrancy attack

It is important to protect digital assets stored in smart contracts. Smart contracts are responsible for the transfer of these assets to their owner on demand. However, an underdeveloped smart contract with security bugs can allow a hacker to siphon off all assets using a reentrancy attack. It can have serious consequences because it has the capability to whisk away all funds from the contract.

A reentrancy attack happens when a smart contract implements a function that transfers an asset to an address belonging to a third party. In such cases, a hacker writes a malicious smart contract that acts as one of the users of the smart contract. The malicious smart contract then calls the methods that initiate the transfer of assets; however, it traps the response and makes a recursive callback for the withdrawal of assets. The recursion will continue as long these funds are within the contract.

A reentrancy attack happens because of a lack of proper smart contract...